Ohkubo T, Okishige K, Goseki Y, Matsubara T, Hiejima K, Ibukiyama C
Second Department of Internal Medicine, Tokyo Medical College, School of Medicine, Japan.
Jpn Heart J. 1998 May;39(3):399-409. doi: 10.1536/ihj.39.399.
We examined the efficacy and safety of ultrasound energy in eliminating the arrhythmogenic substrates of atrial as well as ventricular tissue using a newly developed instrument in both in vivo and in vitro experiments. Ultrasound (US) applicators were tested on 79 lesions created on a beating heart in canine cardiac tissue, and on 64 lesions in porcine heart specimens. US lesions were created by using transducers with frequencies around 5-10 MHz. In the in vivo study, we observed a significant decrease in the amplitude of the electrograms recorded from the tip of the ablation catheter during the US application (p < 0.01). In some sites transmural lesions could be created which were well demarcated. Blood coagulum formation was observed on the tip of the ablation catheter on several occasions. In one dog ventricular fibrillation was provoked by the delivery of ultrasound energy to the left ventricle. In the in vitro study, lesion depth increased significantly with a longer duration of energy delivery when the temperature was maintained table (p < 0.001), and the lesion depth increased significantly with higher temperatures of energy delivery when the duration of US application was maintained (p < 0.05). In both cases, no significant change in surface area was observed. The maximum depth of the lesion was 10.3 mm.
An ultrasound energy system is relatively safe and effective for creating lesions large enough to eliminate arrhythmogenic substrates deep in the ventricular myocardium. Although the US system is free from pop phenomenon, the problem of blood coagulation on the catheter tip remains to be settled.
我们使用一种新开发的仪器，在体内和体外实验中研究了超声能量消除心房和心室组织致心律失常基质的有效性和安全性。超声（US）施加器在犬心脏组织跳动心脏上产生的79个损伤以及猪心脏标本中的64个损伤上进行了测试。使用频率约为5 - 10 MHz的换能器产生US损伤。在体内研究中，我们观察到在施加US期间，从消融导管尖端记录的电图振幅显著降低（p < 0.01）。在一些部位可以形成界限清晰的透壁损伤。在几次实验中，在消融导管尖端观察到血凝块形成。在一只狗中，向左心室输送超声能量引发了室颤。在体外研究中，当温度保持稳定时，随着能量输送时间延长，损伤深度显著增加（p < 0.001），并且当US施加时间保持不变时，随着能量输送温度升高损伤深度显著增加（p < 0.05）。在这两种情况下，表面积均未观察到显著变化。损伤的最大深度为10.3毫米。
超声能量系统相对安全有效，能够产生足够大的损伤以消除心室心肌深处的致心律失常基质。尽管US系统没有爆发现象，但导管尖端的凝血问题仍有待解决。
